China and Vietnam should oppose any "attempt to mess up Asia-Pacific", President Xi Jinping said Wednesday during a trip to Hanoi, as Beijing seeks to counter expanding US influence with the communist nation.

The trip is Xi's first to neighboring Vietnam in six years, and the two nations committed to deeper ties and signed more than 30 agreements, including a pledge to develop rail links between Vietnam and China.

The two-day visit comes after Hanoi upgraded diplomatic ties with Washington when US President Joe Biden visited in September.

Xi said China and Vietnam "should be vigilant against and oppose any attempt to mess up Asia-Pacific", according to Xinhua, China's official state news agency.

"We should strengthen coordination and cooperation in international affairs, and jointly maintain a sound external environment," Xi said.

Biden's visit was part of US efforts around the world to contain China's rising economic power — and to secure supplies of crucial materials needed for high-tech manufacturing.

China and Vietnam said in a joint statement Tuesday they would "continue to deepen and increase bilateral relations".

They agreed to build a "community with a shared future", and said the visit was a "historic landmark in bilateral ties… contributing to peace and stability and development in the region and the world".

Vietnam has long pursued a "bamboo diplomacy" approach, striving to stay on good terms with both China and the United States.

It shares US concerns about Beijing's increasing assertiveness in the contested South China Sea, but it also has close economic ties with China.

Xi said Wednesday that China was ready to work with Vietnam to "find a long-term solution to maritime issues" and help reach a "substantive and effective Code of Conduct in the South China Sea", according to Xinhua.

On Wednesday, Xi laid a wreath at the mausoleum of revolutionary leader Ho Chi Minh and met with Vietnam's Prime Minister Pham Minh Chinh and President Vo Van Thuong.

Chinh said Vietnam was committed to "supporting China to strongly develop, promoting its role as a major country with important contributions to the international community, supporting initiatives by comrade Xi Jinping for peace, cooperation and development in the world".

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© Agence France-Presse